Howdy from Tucson!
Recumbent and Tandem Rider Magazine is a good source and best of all it's FREE; check some of your local bike shops.
Browsing the Internet, of course, works; as you have already found out!
While you are probably going to do this anyway, make sure you go to a bike store that has several brands & styles of tandems. Certain features that I thought we would want turned out to be a hinderance and certain models had a better fit/feel than others. First hand test riding is an absolute must IMHO.